32 THE LIVER-FLUKE. 



c. The vesicula seminalis is an elongated sac lying 



above, and somewhat in front of, the ventral 

 sucker. 



d. The ductus ejaoulatorius is a fine tube running 



from the vesicula seminalis to the end of the 

 penis. When the penis is withdrawn this duct 

 is thrown into convolutions. 



8. The penis or ' cirrus ' is a large muscular organ 

 which lies, when withdrawn, within the cirrus sac, 

 a space in front of the ventral sucker. It can be 

 protruded by evagination, and the ejaculatory 

 duet then lies within it. 



f. The cirrus-sac is a cavity between the ventral sucker 

 and the genital aperture. The penis lies in it 

 when withdrawn, as do also the vesicula seminalis 

 and a small accessory gland which surrounds the 

 ejaculatory duct. 



2. The female organs. _ 



a. The ovary is branched and tubular : it lies on the 



right, or rarely on the left side in front of the 

 anterior testis, and its branches unite to form the 

 narrow ovarian duct. 



b. The yolk-glands are very numerous small rounded 



masses, scattered along two areas extending 

 along the sides of the body from end to end, and 

 each nearly one quarter of the whole width of the 

 animal. 



c. The vitellarian ducts, or ducts of the yolk-glands, 



unite to form an anterior and a posterior duct on 

 each side. These unite about thejunctionof the 

 anterior and middle thirds of the animal, forming 

 a transverse duct, which runs inwards to open 

 into the median yolk-reservoir : from this a single 

 median vitellarian duct runs a short distance 

 forwards and unites with the ovarian duct to form 

 the oviduct. 



